Electric switch indexing mechanism



April 25, 1939. G. H. HART ELECTRIC SWITCH INDEXING MECHANISM Filed June5, 1937 III) g'ywa rvloc GEORGE fiQUEM NEQRT Patented Apr. 25, 1939UNITED STATES PATENT A omen 7 Claims.

switches of the so-called slow make and break\ type andhaving anoperating spindle provided pressed members engaging against theperiphery oi the plate; the arrangement being such that when the starwheel is turned, the spring pressed members ride up the lobes, and whenthe'apexesof the lobes pass the spring pressed membels,

the latter ride into the recess between the lobes.

It is the aim of the present invention to provide certain improvementsover this type of indexing mechanism and more particularly to provide animproved arrangement which will give the operator more or less the feelof a snap action such as is present in so-called snap actionswitches toassure him that the switch has'been shifted to a desired position. Myimproved indexing mechanism is rendered more positive in its operation;there being a pronounced. click when the switch is brought to itsindexed posi- 80 ti'ons, and sticking of the switch in intermediatepositions is avoided.

It is a further aim of the invention to provide,

in a switch of the character described, an improved arrangement throughwhich the cant;

85 carried by the switch spindle operate the swi A further object ofthis invention resides in the provision of an electrical switch of thetype described having various features of novelty and advantageand'which is particularly characterized by its simplicity ofconstruction, ease of assembly, economy of manufacture, and efliciencyof operation.

Other objects will be in part obvious part pointed out more in detailhereinafte The invention accordingly consists in the fea I tures ofconstruction, combination of elements and arrangement of parts whichwill be exempliin the construction hereafter set forth and the"scope ofthe application of whicli wlll be indicatedinthe appended claims.

Figure 1 is a longitudinal section through the switch showing itsoperating parts," a

(01. 14-521) This invention relates generally to electric Fig. 2 is across section taken substantially along the line 2-2 of Fig. 1;

Fig. 3 is a cross section taken substantially along the line 3-3 of Fig.1;

Fig. 4 is a bottom fragmentary view of the 3 switch; and

Figs. 5, 6, and '7 are enlarged fragmentary views taken substantiallyalong the line H of Fig; 1 and showing successive positions of theindexing mechanism while the switch is being 10 shifted.

In accordance with this invention, there has been provided an electricswitch having an operating spindle Ill rotatable in either direction tosuccessive restpositions for operating one or 13 more switch arms whichare arranged to make and break desired circuits. The switch includes anindexing mechanism having a plurality of cooperating indexing cams 'orplates mounted on the spindle and engaged by splingpressed balls 20 orsimilar members which locate the switch in its operative or restpositions and oppose the initial spindle movement froinone rest positionto a successive rest position. After a predetermined initial spindlemovement as controlled by 15 a suitable operating menmer or handle, theindexing mechanism will cooperate with the handle to hasten the shaftrotation to the successive rest position and complete the spindlemovement.

Referring to the drawing, there has been pro vided a casing I! ofsuitable insulating material and having side walls I and I1interconnected by a rear wall II and a bottom wall IS. The side wallsand rear wall extend below the bottom wall, and a short front wall 20 itprovided ,3

, forming a cavity 20' on the under side of the switch within which areone or more switch arms. A cover 2|of suitable insulating material issecured in the outer end of this cavity, as by screws, to protect theswitch arms within the cavity and provide access thereto. In the presentshowing, there is provided three switch arms 22, 23, and 2! which arerespectively operated' by tappets 22'. 23', and. 24' slidably mountedfor free axial movement within bores passing through bottom wall lladjacent the switch arms. The tappets are supported by the-J switch armsand operated by cams, as will be later described. The inner ends of theswitch arms are rigidly secured to terminal plats 25 mounted on thecasing and having screws 25' to facilitate electrical in a-circuit. mefree outer -.end ofeach switch min; a suitable contact1point-Premova'bly engageable withaslmiiar contact point P on asuitableterminal plate 28 secured'to the casing and having connection screws26'. In the present instance, the switch arms are shown as beinginherently resilient and normally tending to assume closed circuitpositions with the contact points in electrical engagement. However, itwill be evident that the switch arms may be spring urged into closedpositions in various other ways without deviating from the scope of thepresent invention. It will be fur- -ably received within rabbetedportions of easing l and secured in position as by screws passingthrough the cover into rear wall l8 and as by screws passing through abent over vlip 28" at the lower end of the front wall and into threadedholes 30 in the casing.

rigidly secured to the shaft with their corresponding lobes anddepressed portions in alignment. Intermediate plate 44 is generallysimilar in contour to plates 42 and 43 with the exception that the lobes441 corresponding to lobes 42' are somewhat larger and of slightlygreater radial extent from the axis of spindle III. Plate 44 hasdepressed portions 44' similarly spaced to depressions 42" and at thesame radial distance from the axis of spindle ID. This intermediate"plate is lost motion connected to the index member (in the presentinstance, plate 43) as by pins 46 laterally projectingfrom plate 43 andreceived in arcuate slots 46' in plate 44. These slots are concentricwith the spindle and permit a slight amount ofrotary lost motionmovement of the intermediate plate with respect to the plates at eachside thereof. After the completion of this slight lost motion, all ofthe plates are constrained to rotate together as a unit.

" A pair of spring pressed balls 48 received within opposedtubularportions 43 of a housing 50 'are resiliently urged, as by springs5|, into Spindle Ill which operates the switch mechanism is journalledat its forward end in a bearing 3| supported by the front cover wall 28'and at its rearward end in a bracket 33 depending from and secured totop wall 28. Hence, the spindle and cam assembly and an indexingmechanism, to be later described, is removable as a unit with the coverto facilitate assembly and accessibility to the various switch parts.

Bearing 3| projects forwardly from cover 2l and has external threads 3|receiving a nut3l" so that-the switch may be conveniently secured to awall or panel in a single hole type of mounting. Spindle I0 extendsforwardly from hearing 3| and has a suitable insulating handle 34fastened thereon, as by a screw 35.

The tappets are respectively engaged and depressed by cams on spindleIt! so that rotation of the spindle to predetermined rest positions willoperate the switch and-establish desired circuits. In the presentshowing, there are provided three cams 22.", 23", and 24" rigidlysecured to the spindle in spaced relation and respectively engageablewith the tappets 22, 23, and 24 to control the o'peningand closingmovements of the switch arms '22, 23, and 24. Each tappet has apartispherical head to facilitate a and . ties of opposed lobes 4.4engage balls 43, as shown.

tween plates 42 and 43. In the present instance,

theswitch is shown as having four operative positions so thatthe platesare each-provided with four lobes and depressed portions respectivelylocated between each pair of lobes: It

I will be-appreciated, however; that the number of lobes and depressionson each plate is de- 7 pendent solely on the number of positions towhich the switch is to be shifted.

Plates 42 and 43, which have uniformly spaced duplicate symmetricallobes 42' and. uniformly simultaneous opposed engagement with the platecontours, as shown in Figs.5, 6, and 7. Housing 50, which may besuitably formed from metal bent to shape and secured to front wall 23',is centrally apertured to freely receive spindle I 0 therethrough and topermit rotation of the'index plates. The ends of the tubular portionsare provided with bent over cars 52 arranged to compressively secure theballs and spring assemblies in position. Since the depressed portions ofthe index plates are ofcorresponding size and correspondingly located,it will be appreciated that.

under normal conditions the balls will, be received inopposed relationin similar depressed portions of each plate to secure the switch in itspreset position.

When the spindle I3 is rotated in'elther direction, herein illustratedin a clockwise.direction, plates 42 and 43 will integrally rotate withthe spindle and the initial rotation of plate 44 will be retarded bythe. spring pressed engagement of the balls thereagainst. The peripheralcontours of the, lobes 44' are such that when the lost motion has beentaken up by pins 46 within slots, 46' (Fig. 7) lobes 44' will in effectconstitute a smooth peripheral continuation of that portion of the lobes42' engaged'bythe spring pressed balls, causing the balls to ride pastand out of contact with lobes, 42'. Hence, the initial rotationalmovement of spindle Ill and the index plates under'influence of handle34 will store up energy in springs 5| until the radial extremiin Fig.-7. Further movement of spindle ID in the same direction will now causethe balls to ride downwardly on the other sides of the lobes 44f andinto seated engagement with the next su':cee'dlng set of depressedportions to a positipn similar to that of Fig. 5 to again locate theswitch in a rest position. The intermediatejtation after the balls ,moveover the radial extremities of the lobes 44', resulting in a snappingactionrwhich produces an audible click and is felt by the operator tosignal to him that the switch has shifted to the succeeding restposition;

It will thus be appreciated that the index spaced duplicate depressedportions 42", are plates cooperate with each other and with handle N tointroduce a positive operation of the switch and to definitely positionthe switch when the handle is turned to shift the switch to itssucceeding rest position. The switch cannot stick in an intermediateposition of its movement since the plates 43 and 4d are lost motionconnected and the lobe of each plate has sharply sloping contoursmeeting at a point. Hence, the balls 48 will always tend to seat indepressed positions of the plates. Furthermore, the provision of tappetsslidably mounted in the casing and engageable with the switch armsprovides a substantial straight line movement of switch operationwithout producing undesirable wear or friction frequently found in othertypes of switches.

As many changes could be made in the above construction and manyapparently widely different embodiments of this invention'could be madewithout departing from the scope thereof, it is intended that all mattercontained in the above description or shown in the accompanying drawingshall be interpreted as illustrative and not in a limiting sense.

It is. also to be understood that the language used in the followingclaims is intended to cover all of the generic and specific features ofthe invention herein described and all statements of member, and amember resiliently urged against the perimeters of said plates.

2. In an electric switch, indexing means comprising a rotary operatingmember, index plates on said spindle having similarly positioned spacedlobes and depressed portions, one of said plates having limited rotarymovement with respect to another of said plates fixed to said member,the lobes of said, first plate extending beyond the corresponding lobesof said second plate, and a member resiliently urged against said platecontours and normally seating within corresponding depressed portions ofsaid plate to position the switch in indexed positions.

3. In an electric switch, indexing means comprising, a spindle rotatablein both directions, means responsive to the spindle rotation to operatethe switch arm, an inde'x plate rigidly secured tothe spindle and havinga plurality of spaced lobes and depressed portions, a. second plategenerally similar in contour to the first plate and journalled on thespindle adjacent thereto, a lost motion connection between said plates,the lobes of said second plate radially extending beyond the lobes ofthe firstlplate, and a spring pressed member engageable with thecontours of said plates whereby the lobes 01' Said tion between theplates plates will cooperate with said member to aid in rotating thespindle to successive predetermined positions after an initial spindlemovement.

prising a'spindle rotatable in either direction to predeterminedpositions, adjacent generally similar indexplates on said spindle andhaving similarly positioned spaced lobes and depressed portions,- one ofthe plates being freely rotatable and the otherbeingirigidly secured tothe spindle, one of said plates -t having an aperture therethroughreceiving a pin laterally projecting from the other plate to providaalost'motion connecsaid freely rotatable plate having lobes exten ingbeyond the corresponding lobes of the other plate, and a spring pressedmember engageable with the peripheries of said plates.

5. In an electric switch, indexing means comsecond plate, and a springpressed ball engage able with the peripheries of the plates. 6. In anelectric switch, indexing means comprising an-operating splndlerotatable to predetermined positions, a pair of adjacent index plates onthe spindle and of generally similar contour, one of said plates beingfreely rotatable and lost motion connected to the other which is rigidlysecured to thespindle, each plate having uniformly spaced lobes andintervening depressed portions, said first plate having its lobesradially extending beyond the corresponding lobes of said second plate,and a spring pressed member engageable with the plate peripheries, thecontours of corresponding lobes engaged by the member being such thatthe contour of the engaged lobe of the first plate will serve as acontinuation of the corresponding contour on the second plate.

7. In an electric switch, indexing-means comprising an operating spindlerotatable in either direction to predetermined' positions, a pair offixed spacedindex plates onthe spindle and having duplicate alignedperipheral contours provided with uniformly spaced lobes and interveningdepressed portions, an intemediate plate of generally similar peripheralcontour lournalled on the spindle between said other plates and lostmotion connected to one of said other plates and having lobes radiallyextending beyond the'corresponding lobes of said other plates, and aspring pressed ball engageable with the plate contours, the contour ofthedntermedlate plate engaged bythe ball merging with and serving as acontinuation of the corresponding contour of said other plates after theintermediate plate has been shifted to its lost motion position.

GEORGE HEGEMAN HART.

